JP2002193171A - Intake device for unit swing type engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an intake device for a unit swing type engine that can increase the capacity of an air cleaner with simple constitution and heighten the rigidity of a transmission case. SOLUTION: This intake device is provided for the unit swing type engine provided with a transmission mechanism 24 having a drive pulley 25, a V-belt 26 for transmitting the drive of the drive pulley 25, and a driven pulley 28, to which the rotation of a crankshaft 23 is transmitted through the V-belt 26, for transmitting the drive to a rear axle 27 to which a rear wheel 12 is journalled; and the transmission case 31 for accommodating the transmission mechanism 24. The transmission case 31 is provided with a V-belt chamber 32 for accommodating the V-belt 26, the drive pulley 25 and the driven pulley 28 inside; and a chamber 33 with an isolated space between the drive pulley 25 and the driven pulley 28 independently of the V-belt chamber.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of a unit swing type engine, and more particularly to an intake device for a unit swing type engine of a motorcycle.

[0002]

2. Description of the Related Art Conventionally, in the case of a so-called scooter type motorcycle, it is necessary to increase the capacity of a utility box below a seat in order to enhance commercial value. To increase the capacity of the utility box, lay the air cleaner behind the engine,
Alternatively, a space is provided by reducing the diameter of the cleaner outlet or reducing the capacity occupied by the intake system. However, there is a problem that the space occupied by the device below the seat is limited, so that the layout of the intake system is restricted. Further, as for the cleaner outlet, since the frame line is pushed down by enlarging the utility box, the diameter of the ventilation path has to be reduced.

Therefore, as a countermeasure for the above-mentioned conventional problems,
As disclosed in JP-A-61-175124, in a unit swing type engine, an air cleaner is formed integrally with a transmission case in which a transmission device for transmitting the driving of the engine to the rear wheels is housed. There has been proposed a technique of cooling a V-belt for transmitting drive by guiding outside air to a transmission case.

According to this method, when an air cleaner is formed integrally with a transmission case, the intake path of the engine cools the V-belt after passing through the air cleaner and then guides the V-belt to the carburetor. Since there is a possibility that abraded pieces of the V-belt may be sucked into the engine, the V-belt is cooled and then guided to the air cleaner, so that the space of the transmission case is effectively used.

[0005]

However, there is a problem that some of the wear pieces of the V-belt are large and cause clogging of the air filter. Further, although the configuration is such that the internal space of the transmission case is used, since no standing wall or the like is provided inside the interior, it is necessary to form a reinforcing rib similarly to the conventional transmission case to increase the rigidity of the transmission case.

As a measure for increasing the rigidity of the transmission case, a recess is provided in the cover of the transmission case of the engine, as disclosed in Japanese Patent Application Laid-Open No. 2000-25670.
It has been proposed to form an enlarged portion of the air cleaner in the recess, integrally form a cleaner case with the transmission case, and provide the transmission case with a case cover. According to this method, although the capacity of the air cleaner is increased and the rigidity of the case cover is increased, there is a problem that the rigidity of the transmission case itself is not increased.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems, and has a simple structure to increase the capacity of an air cleaner and increase the rigidity of a transmission case. The purpose is to provide.

[0008]

SUMMARY OF THE INVENTION The present invention relates to an intake device for a unit swing type engine, and includes a drive pulley connected to a crankshaft, a V-belt for transmitting the drive of the drive pulley, and a V-belt through the V-belt. A unit swing type including a transmission mechanism having a driven pulley for transmitting the drive to a rear axle on which a rear wheel is rotatably transmitted while the rotational motion of the crankshaft is transmitted, and a transmission case accommodating the transmission mechanism. In the engine, the transmission case has a V-belt chamber in which the V-belt, the driving pulley, and the driven pulley are housed, and a space separated from the V-belt chamber between the driving pulley and the driven pulley. A chamber having a ventilation path upstream communication hole communicating with the air cleaner box. And a ventilation path downstream communication hole communicating with the carburetor, and communicates the outlet of the air cleaner box into the chamber through the ventilation path upstream communication hole, and the carburetor through the ventilation path downstream communication hole. Is connected to the chamber chamber.

It is preferable that the air cleaner box is provided integrally with the transmission case on an outer upper portion of the transmission case. Further, it is preferable that the chamber is formed integrally with the transmission case in a cantilever manner.
In addition, it is preferable that a downstream ventilation path from the chamber to the carburetor communicates with the carburetor by conducting from the upper side of the transmission case closer to the driving pulley than the chamber to the outside of the case. Further, it is preferable that the ventilation path is provided inside the vehicle body frame widening portion in the vehicle width direction.
In the unit swing type engine, it is preferable that the cylinder is disposed to be inclined substantially horizontally forward, and that a lower portion of the cylinder communicates with an exhaust passage and an upper portion communicates with an intake passage.

According to the present invention, the following effects can be obtained. That is, in the intake device of the unit swing type engine, the transmission case of the transmission device has a V-shaped housing in which the V-belt, the driving pulley and the driven pulley are housed.
By providing a belt chamber and a chamber chamber having a space separated from the V-belt chamber between the driving pulley and the driven pulley, it is possible to prevent V-belt wear pieces from entering the chamber. Can be.

Further, the chamber has an air passage upstream communication hole communicating with the air cleaner box, and a air passage downstream communication hole communicating with the carburetor, and the air cleaner box passes through the air passage upstream communication hole. By communicating the outlet of the carburetor into the chamber and the inlet of the carburetor through the communication hole on the downstream side of the ventilation path, the cleaner capacity can be secured without having to take a large capacity of the air cleaner box. As a result, the air intake performance can be improved, and the size of the air cleaner box attached to the outside of the transmission case can be reduced, so that a layout space for peripheral components can be secured. Further, since the partition member forming the chamber functions as a reinforcing member, the rigidity of the transmission case can be increased.

[0012] Further, by providing the air cleaner box integrally with the transmission case on the upper outside of the transmission case, stones and mud that have been thrown up by the wheels during traveling are less likely to hit the air cleaner box, and the air cleaner box is reduced in size. As a result, interference with the vehicle body frame can be prevented.

[0013] Further, by integrally forming the chamber chamber with the transmission case in a cantilever manner, the structure can be simplified, the assembling work can be facilitated, and the number of steps can be reduced.

[0014] Further, the downstream ventilation path from the chamber to the carburetor communicates with the carburetor from the upper side of the transmission case on the drive pulley side from the chamber to communicate with the carburetor. Since the space can be effectively used, it is possible to prevent the transmission case from becoming large.

[0015] Further, by disposing the downstream ventilation path inside the vehicle body frame widening portion in the vehicle width direction, the vehicle body frame is arranged more inside the transmission case and more rearward in the vehicle width direction. Even if there is, the layout can be performed without interference between the downstream ventilation path and the vehicle body frame.

Further, in the unit swing type engine, the cylinder is disposed to be inclined substantially horizontally forward, and the lower portion of the cylinder communicates with the exhaust passage, and the upper portion communicates with the intake passage. Since the length can be shortened, it is possible to suppress the vibration during traveling and the vibration of the intake passage caused by the operation of the engine unit, and it is possible to prevent the connection portions from becoming loose.

[0017]

Embodiments of the present invention will be described below in detail with reference to the drawings. 1 to 5 show an example of the embodiment of the present invention. In the drawings, portions denoted by the same reference numerals as those in the drawings represent the same components. FIG. 1 is an overall side view showing an overall configuration of a scooter type motorcycle employing an intake device for a unit swing type engine according to an embodiment of the present invention, FIG.
3 is a side view showing the overall configuration of the engine, FIG. 3 is a cross-sectional view taken along the line AA of FIG. 2, showing the configuration of the engine, and FIG. 4 is a view B of FIG. FIG. 5 is a cross-sectional view taken along a line B-C of FIG. 4, showing a configuration of the transmission case according to the present embodiment.

As shown in FIG. 1, the present embodiment is a scooter type motorcycle 1 employing an intake device for a unit swing type engine according to the present invention. ), The handlebar 4 is held, and the front wheel 6 is rotatably held by a front fork 5 connected below the handlebar 4. A seat 7 is held behind the front part 3 of the vehicle body, and between the front part 3 of the vehicle body and the seat 7, a vehicle traveling direction in which an occupant on the seat 7 can place both feet. A floor unit 10 is formed by a pair of left and right footrests 8 and a center console 9 rising upward between the footrests 8.

A rear cover 11 is provided behind the floor portion 10 to cover a rear portion of the vehicle body. Below the rear cover 11, a unit swing type engine 2 is swingably provided on a vehicle body frame. The rear wheel 12 is attached to the vehicle. Above the rear wheel 12, the rear fender 1
8 is fixed to the rear cover 11 and covers the rear wheel 12. A seat 7 is provided on the upper side of the rear cover 11 over substantially the entire length behind the vehicle body.
A storage box 19 is formed on the lower side. The seat 7 serves as a lid of the storage box 19.

In the unit swing type engine 2, as shown in FIGS. 2 to 5, a cylinder 21 is disposed to be inclined substantially horizontally forward, and in a crankcase 22 behind the cylinder 21, the width of the vehicle body extends in the axial direction. And a crankshaft 23 is disposed. A transmission mechanism 24 for transmitting drive to the rear wheels 12 is provided on the left rear side of the engine 2 in the vehicle body traveling direction.
Is provided. An exhaust duct 20a is provided on the lower side of the cylinder head 20 disposed in front of the cylinder 21.
, While an intake duct 20b is connected to an upper portion thereof.

The transmission mechanism 24 includes a drive pulley 25 connected to the crankshaft 23, a V-belt 26 for transmitting the drive of the drive pulley 25, and a V-belt 2.
6, the rotational motion of the crankshaft 23 is transmitted, and the rear axle 2
And a driven pulley 28 for transmitting drive to the crankcase 7, and is housed in a transmission case 31 formed integrally with the crankcase 22.

The transmission case 31 has a V-belt chamber 32 in which the driving pulley 25V, the driven pulley 28 and the belt 26 are accommodated, and a V-belt chamber 32 between the driving pulley 25 and the driven pulley 28. And a chamber room 33 having an isolated space.

The chamber 33 is provided with the transmission case 31.
In a cantilevered state toward the outside in the vehicle width direction from the inner wall of the drive pulley 25, the drive pulley 25 and the driven pulley 28 are integrally formed so as to protrude, and have a box shape. The chamber chamber 3
An upper side communication hole 33b communicating with the air cleaner box 40 and a downstream side communication hole 33c communicating with the carburetor 41 are formed in the upper side surface 33a.

The suction passage is communicated from the outlet 40a of the air cleaner box 40 to the chamber 33 through the upstream communication hole 33b, passes through the chamber 33, and is connected to the downstream communication hole 33c. Of the carburetor 41 via the cleaner outlet 42
a.

The air cleaner box 40 is provided integrally with the transmission case 31 on the upper outside 30a of the transmission case 31. The upstream side intake passage 43 from the air cleaner box 40 to the chamber room is connected to the outside of the case from the upper surface of the transmission case 31 on the driven pulley 28 side from the chamber room 33 by the air cleaner box 40.
Is in communication with

On the other hand, the cylinder 21
Downstream intake passage 4 to carburetor 41 provided above
4 is connected to the carburetor 41 by conducting from the upper side of the transmission case 31 on the drive pulley 25 side to the outside of the case via the cleaner outlet 42 from the chamber 33. The downstream side intake passage is provided with the body frame widening portion 45.
It is disposed so as to be inside the vehicle width direction.

The intake device 30 according to the present embodiment includes the above-described chamber 33, an air cleaner box 40, a carburetor 41, a cleaner outlet 42, an upstream intake passage 43, and a downstream intake passage 44.

Next, the intake operation of the intake device 30 of the present embodiment will be described. As shown in FIGS. 2 to 4, the air introduced into the air cleaner box 40 is sent into the chamber 33 through the upstream intake passage 43.
Then, the stable air in the chamber 33 is sent to the carburetor 41 through the downstream intake passage 44, and is sent to the intake port (not shown) via the carburetor 41.

With the above-described structure, according to the present embodiment, since the chamber chamber 33 is formed in the transmission case 31, the mounting position of the air cleaner box 40 is not largely changed, and the size of the air intake device is increased. Thus, the capacity of the air cleaner can be increased without the need. Further, a V-belt chamber 32 formed in the transmission case 31 is provided.
Since the chamber chamber 33 is configured so as to be isolated from the air conditioner, there is an effect that V-belt wear pieces and the like do not enter during the intake.

Further, since the chamber 33 has a box structure, the rigidity of the transmission case can be ensured without using a conventional grid-like rib in order to have rigidity. This makes it possible to reduce the weight of the engine.

In the present embodiment, the downstream side intake passage 4
4 is routed to the drive pulley 25 side in the space inside the transmission case 31 and, when it is led out of the transmission case 31, is disposed so as to be inside the vehicle body frame widening portion 45 in the vehicle width direction. A layout of the intake passage with good space efficiency without interference can be realized. Thereby, the effect that the degree of freedom of the pipe diameter of the cleaner outlet 42 can be obtained can also be obtained.

In the present embodiment, the unit swing type engine is configured such that a cylinder is disposed substantially horizontally forward and inclined, and a lower portion of the cylinder communicates with an exhaust duct 20a and an upper portion communicates with an intake duct 20b. Thus, the intake passage can be shortened, so that vibration during traveling and vibration of the intake passage caused by operation of the engine unit can be suppressed, and loosening of each connection portion can be prevented.

In the present embodiment, the chamber 33 is formed integrally with the transmission case 31 and is formed so as to protrude into the transmission case 31. 33 is not limited to the shape and the structure, for example, 2 in FIG.
As shown by a chain line, the transmission case 31 may be fixed to the cover 31a with fastening bolts 33d from the cover 31a side. According to this method, the central portion of the cover 31a is fixed to the transmission case 31 through the chamber 33, and the cover 31a is reinforced by the chamber 33. Therefore, the rigidity of the transmission case 31 can be further increased. it can.

Further, the intake device of the unit swing type engine of the present invention is not limited to the illustrated example described above, and it is needless to say that various changes can be made without departing from the gist of the present invention. .

[0035]

As described above, according to the first aspect of the present invention,
According to the intake device for a unit swing type engine described in any one of the first to sixth aspects, the capacity of the air cleaner can be increased with a simple configuration, and the rigidity of the transmission case can be increased. That is, by providing a chamber room having a space separated from the V-belt room between the driving pulley and the driven pulley inside the transmission case, the cleaner capacity can be increased without taking a large capacity of the air cleaner box. Therefore, the intake performance can be improved, the size of the air cleaner box attached to the outside of the transmission case can be reduced, and a layout space for peripheral components can be secured. Further, it is possible to prevent the V-belt wear pieces from being mixed into the chamber. Further, since the partition member forming the chamber works as a reinforcing member, the rigidity of the transmission case can be increased.

[Brief description of the drawings]

FIG. 1 is an overall side view showing an overall configuration of a scooter type motorcycle employing an intake device for a unit swing type engine according to an embodiment of the present invention.

FIG. 2 is a side view showing the overall configuration of the engine.

FIG. 3 is a sectional view taken along the line AA of FIG. 2 showing the configuration of the engine.

FIG. 4 is a sectional view taken along the line BB of FIG. 3 showing the configuration of the intake device according to the present embodiment.

FIG. 5 is a diagram showing a configuration of a transmission case according to the embodiment.
It is a CC sectional view taken on the line of FIG.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 scooter type motorcycle 2 unit swing type engine 19 storage box 24 transmission mechanism 25 drive pulley 26 V belt 28 driven pulley 30 intake device 31 transmission case 32 belt room 33 chamber chamber 40 air cleaner box 41 carburetor 42 cleaner outlet 43 upstream intake passage 44 Downstream intake passage

Claims (6)

[Claims] 1. A drive pulley connected to a crankshaft, a V-belt for transmitting the drive of the drive pulley, a rotational motion of the crankshaft being transmitted via the V-belt, and a rear wheel being pivotally supported. A transmission mechanism having a driven pulley that transmits drive to a rear axle to be driven, and a unit swing type engine including a transmission case that houses the transmission mechanism, wherein the transmission case has the V-belt, the drive pulley, and A V-belt chamber for accommodating a driven pulley; and a chamber chamber having a space separated from the V-belt chamber between the driving pulley and the driven pulley. The chamber chamber communicates with an air cleaner box. A ventilation path upstream communication hole, and a ventilation path downstream communication hole communicating with the carburetor; While communicating the outlet of the air cleaner box into the chamber through the flow-side communication hole,
An intake device for a unit swing type engine, wherein an inlet of a carburetor communicates with a chamber through a communication hole on the downstream side of the ventilation path. 2. The air intake device for a unit swing type engine according to claim 1, wherein the air cleaner box is provided integrally with the transmission case on an outer upper portion of the transmission case. 3. The intake device for a unit swing type engine according to claim 1, wherein the chamber chamber is formed integrally with the transmission case in a cantilever manner. 4. The carburetor according to claim 1, wherein a downstream ventilation path from the chamber to the carburetor communicates with the carburetor from the upper side of the transmission case closer to the driving pulley than the chamber to the outside of the case. The intake device for a unit swing type engine according to any one of Claims 3. 5. The intake device for a unit swing type engine according to claim 1, wherein the ventilation path is provided inside the vehicle body frame widening portion in the vehicle width direction. . 6. The unit swing type engine according to claim 1, wherein a cylinder is disposed to be inclined forward substantially horizontally, and a lower portion of the cylinder communicates with an exhaust passage and an upper portion communicates with an intake passage. The intake device for a unit swing type engine according to any one of claims 1 to 5.